Antarctic sea ice mystery thickens ... literally

Antarctic sea ice is increasing - that's old news - but now it's also thicker than scientists thought, and that's only adding to the confusion.

A project to map Antarctic sea ice over the last four years from below using an underwater robot has produced the most detailed images of the sea ice to date, surveying an area of 500,000 square meters, or a fifth of a square mile.

For years the expanding sea ice in the Antarctic has been the focus of a lot of research, and a source of controversy, with climate change skeptics claiming it offsets the wide scale melting of Arctic sea ice.

ANTARCTICA - UNDATED:***EXCLUSIVE*** Iceberg floating off the western Antarctic peninsula, Antarctica, Southern Ocean. Humans may have spent thousands of year perfecting art and architecture but these incredible photographs of spectacular icebergs show they are no match for nature's grand designs. Captured off the Western Antarctic peninsula the colossal ice carvings have been whittled away by biting polar winds, water, and chilling sub-zero temperatures to form incredible mega structures that take the breath away. In the vast array of jaw-dropping shapes some icebergs feature towering pillars of ice while others appear to have had bridges and tunnels masterfully bored into their huge floating masses. Some even take on the form of gigantic frosty bridges of ice and snow with intricate 'arches' carved out by the harsh Antarctic conditions. Photogrpaher Steven Kazlowski, 40, witnessed the amazing sights as he toured the world's most southerly continent on a 62-foot engined sailing boat. Against the jaw-dropping Antarctic background each paints a magnificent picture - and even caught the eyes of passing Gentoo penguins and humpback whales. (Photo by Steven Kazlowski / Barcroft Media / Getty Images)

That's what Jay Lehr has argued. Lehr is the science director for the Heartland Institute - a conservative think tank that has repeatedly spoken out against climate change science.

Lehr said, "Global warming activists like to claim global consequences resulting from carbon dioxide emissions, yet they conveniently forget to discuss the global nature of polar sea ice data. Instead, they only talk about Arctic sea ice, because that is the only polar region where sea ice is receding"

But scientists say the melting in the Arctic and the expanding ice in the Antarctic don't really balance each other out at all.

NASA's Dr. Walt Meier put it this way: "That's simply not true. If you look at just simply the magnitude of the changes we're seeing in the winter time, the Arctic is decreasing about twice as fast as what the Antarctic is increasing."

And while scientists haven't pinpointed the main cause of expanding sea ice in the Antarctic, they're not exactly clueless.

RiAus's Paul Willis said, "More rain and snow other effects of climate change could be layering the southern ocean with a cool dense layer on top. Rain and snow could also be freshening the surface waters and thus increasing the local freezing point for sea-ice formation."

Another possible reason is because Antarctic ice is based around a landmass - the continent of Antarctica - cold winds come off the continent and help form more ice, something that doesn't happen in the Arctic.

Adding to the confusion, while Antarctic sea ice is expanding as a whole, there's also a lot of melting going on, at uneven rates.

"Here in the Bellingshausen Sea we find the area of sea ice is shrinking rapidly, compared to other areas of the Antarctic sea ice so therefore we're trying to understand the process of why this area of sea ice in the Bellingshausen sea is reducing," said Jeremy Wilkinson.

Scientists hope this first survey of sea ice thickness can pave the way for more extensive surveys in the future.